With the development of wireless communication system, service requirement of user for high quality, high speed and high services is more and more. The wireless communication operators and equipment providers need to keep improving in order to satisfy the requirement of the user. This requires a large amount of spectrum resources to support new services and satisfy requirement for high speed communication. However, the limited spectrum resources have been allocated to fixed operators and services. New available spectrum is rare and/or expensive. In such case, an idea of dynamically using spectrum has been proposed, that is, spectrum resources which have been allocated to some services but not been exploited are dynamically used. For example, the spectrum of channels on which no program is being broadcasted in the digital television broadcast spectrum is dynamically used to perform wireless mobile communication without interfering with the normal receiving of television signals.
In such application instance, since the television broadcast spectrum per se is used for television broadcast system, the television broadcast system is regarded as a primary system, the television is regarded as a primary user, the mobile communication system is regarded as a secondary system, and the receiver in the mobile communication system is regarded as a secondary user. In other words, the primary system described herein may refer to the system with authority of using spectrum such as the television broadcast system, and the secondary system may refer to the system without authority of using spectrum which can use the spectrum of the primary system or its adjacent spectrum appropriately only when the primary system does not use such spectrum.
This communication manner of the primary and secondary systems coexisting requires that the application of the secondary system does not cause any adverse influence to the application of the primary system, or, the influence caused by the secondary system to the primary system may be controlled to an allowable range of the primary system. In the case that the influence to the primary system is kept in a certain range, the spectrum resources of the primary system may be allocated to a plurality of secondary systems.
Specifically, the primary and secondary systems may operate on the same frequency band or different frequency bands. In the case that the frequency bands used by the primary and secondary systems are adjacent to each other, since the adjacent channel leakage ratio of the transmitter and the adjacent channel selectivity of the receiver, the secondary system still may interfere with the primary system.
Existing provisions, such as Conference of European Posts and Telecommunications (CEPT), “Draft of ECC report: Technical and operational requirements for the operation of white space devices under geo-location approach”, ECC186, January 2013, prescribe how to calculate available primary system spectrum at a certain position, but not prescribe when a plurality of secondary systems need to use the spectrum resources of the primary system, how to selectively allocate the spectrum resources to the secondary systems such that certain performance is better or entire spectrum utilization is more efficient.
In addition, when excess secondary systems share the available primary system spectrum, it is possible that each secondary system obtains a little available spectrum resource, and thereby at least part of the secondary systems can not satisfy the requirement of application. According to the solution proposed in CN101990289A for example, the usage requirements of all of the secondary systems may be calculated, and then the secondary systems which are not advantageous to utilize the spectrum resources of the primary system may be removed according to priority and the like. However, when the number of the secondary systems is large, the system overhead is large.